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Linux/drivers/rtc/rtc-mxc.c

  1 /*
  2  * Copyright 2004-2008 Freescale Semiconductor, Inc. All Rights Reserved.
  3  *
  4  * The code contained herein is licensed under the GNU General Public
  5  * License. You may obtain a copy of the GNU General Public License
  6  * Version 2 or later at the following locations:
  7  *
  8  * http://www.opensource.org/licenses/gpl-license.html
  9  * http://www.gnu.org/copyleft/gpl.html
 10  */
 11 
 12 #include <linux/io.h>
 13 #include <linux/rtc.h>
 14 #include <linux/module.h>
 15 #include <linux/slab.h>
 16 #include <linux/interrupt.h>
 17 #include <linux/platform_device.h>
 18 #include <linux/clk.h>
 19 #include <linux/of.h>
 20 #include <linux/of_device.h>
 21 
 22 #define RTC_INPUT_CLK_32768HZ   (0x00 << 5)
 23 #define RTC_INPUT_CLK_32000HZ   (0x01 << 5)
 24 #define RTC_INPUT_CLK_38400HZ   (0x02 << 5)
 25 
 26 #define RTC_SW_BIT      (1 << 0)
 27 #define RTC_ALM_BIT     (1 << 2)
 28 #define RTC_1HZ_BIT     (1 << 4)
 29 #define RTC_2HZ_BIT     (1 << 7)
 30 #define RTC_SAM0_BIT    (1 << 8)
 31 #define RTC_SAM1_BIT    (1 << 9)
 32 #define RTC_SAM2_BIT    (1 << 10)
 33 #define RTC_SAM3_BIT    (1 << 11)
 34 #define RTC_SAM4_BIT    (1 << 12)
 35 #define RTC_SAM5_BIT    (1 << 13)
 36 #define RTC_SAM6_BIT    (1 << 14)
 37 #define RTC_SAM7_BIT    (1 << 15)
 38 #define PIT_ALL_ON      (RTC_2HZ_BIT | RTC_SAM0_BIT | RTC_SAM1_BIT | \
 39                          RTC_SAM2_BIT | RTC_SAM3_BIT | RTC_SAM4_BIT | \
 40                          RTC_SAM5_BIT | RTC_SAM6_BIT | RTC_SAM7_BIT)
 41 
 42 #define RTC_ENABLE_BIT  (1 << 7)
 43 
 44 #define MAX_PIE_NUM     9
 45 #define MAX_PIE_FREQ    512
 46 static const u32 PIE_BIT_DEF[MAX_PIE_NUM][2] = {
 47         { 2,            RTC_2HZ_BIT },
 48         { 4,            RTC_SAM0_BIT },
 49         { 8,            RTC_SAM1_BIT },
 50         { 16,           RTC_SAM2_BIT },
 51         { 32,           RTC_SAM3_BIT },
 52         { 64,           RTC_SAM4_BIT },
 53         { 128,          RTC_SAM5_BIT },
 54         { 256,          RTC_SAM6_BIT },
 55         { MAX_PIE_FREQ, RTC_SAM7_BIT },
 56 };
 57 
 58 #define MXC_RTC_TIME    0
 59 #define MXC_RTC_ALARM   1
 60 
 61 #define RTC_HOURMIN     0x00    /*  32bit rtc hour/min counter reg */
 62 #define RTC_SECOND      0x04    /*  32bit rtc seconds counter reg */
 63 #define RTC_ALRM_HM     0x08    /*  32bit rtc alarm hour/min reg */
 64 #define RTC_ALRM_SEC    0x0C    /*  32bit rtc alarm seconds reg */
 65 #define RTC_RTCCTL      0x10    /*  32bit rtc control reg */
 66 #define RTC_RTCISR      0x14    /*  32bit rtc interrupt status reg */
 67 #define RTC_RTCIENR     0x18    /*  32bit rtc interrupt enable reg */
 68 #define RTC_STPWCH      0x1C    /*  32bit rtc stopwatch min reg */
 69 #define RTC_DAYR        0x20    /*  32bit rtc days counter reg */
 70 #define RTC_DAYALARM    0x24    /*  32bit rtc day alarm reg */
 71 #define RTC_TEST1       0x28    /*  32bit rtc test reg 1 */
 72 #define RTC_TEST2       0x2C    /*  32bit rtc test reg 2 */
 73 #define RTC_TEST3       0x30    /*  32bit rtc test reg 3 */
 74 
 75 enum imx_rtc_type {
 76         IMX1_RTC,
 77         IMX21_RTC,
 78 };
 79 
 80 struct rtc_plat_data {
 81         struct rtc_device *rtc;
 82         void __iomem *ioaddr;
 83         int irq;
 84         struct clk *clk_ref;
 85         struct clk *clk_ipg;
 86         struct rtc_time g_rtc_alarm;
 87         enum imx_rtc_type devtype;
 88 };
 89 
 90 static const struct platform_device_id imx_rtc_devtype[] = {
 91         {
 92                 .name = "imx1-rtc",
 93                 .driver_data = IMX1_RTC,
 94         }, {
 95                 .name = "imx21-rtc",
 96                 .driver_data = IMX21_RTC,
 97         }, {
 98                 /* sentinel */
 99         }
100 };
101 MODULE_DEVICE_TABLE(platform, imx_rtc_devtype);
102 
103 #ifdef CONFIG_OF
104 static const struct of_device_id imx_rtc_dt_ids[] = {
105         { .compatible = "fsl,imx1-rtc", .data = (const void *)IMX1_RTC },
106         { .compatible = "fsl,imx21-rtc", .data = (const void *)IMX21_RTC },
107         {}
108 };
109 MODULE_DEVICE_TABLE(of, imx_rtc_dt_ids);
110 #endif
111 
112 static inline int is_imx1_rtc(struct rtc_plat_data *data)
113 {
114         return data->devtype == IMX1_RTC;
115 }
116 
117 /*
118  * This function is used to obtain the RTC time or the alarm value in
119  * second.
120  */
121 static time64_t get_alarm_or_time(struct device *dev, int time_alarm)
122 {
123         struct platform_device *pdev = to_platform_device(dev);
124         struct rtc_plat_data *pdata = platform_get_drvdata(pdev);
125         void __iomem *ioaddr = pdata->ioaddr;
126         u32 day = 0, hr = 0, min = 0, sec = 0, hr_min = 0;
127 
128         switch (time_alarm) {
129         case MXC_RTC_TIME:
130                 day = readw(ioaddr + RTC_DAYR);
131                 hr_min = readw(ioaddr + RTC_HOURMIN);
132                 sec = readw(ioaddr + RTC_SECOND);
133                 break;
134         case MXC_RTC_ALARM:
135                 day = readw(ioaddr + RTC_DAYALARM);
136                 hr_min = readw(ioaddr + RTC_ALRM_HM) & 0xffff;
137                 sec = readw(ioaddr + RTC_ALRM_SEC);
138                 break;
139         }
140 
141         hr = hr_min >> 8;
142         min = hr_min & 0xff;
143 
144         return ((((time64_t)day * 24 + hr) * 60) + min) * 60 + sec;
145 }
146 
147 /*
148  * This function sets the RTC alarm value or the time value.
149  */
150 static void set_alarm_or_time(struct device *dev, int time_alarm, time64_t time)
151 {
152         u32 tod, day, hr, min, sec, temp;
153         struct platform_device *pdev = to_platform_device(dev);
154         struct rtc_plat_data *pdata = platform_get_drvdata(pdev);
155         void __iomem *ioaddr = pdata->ioaddr;
156 
157         day = div_s64_rem(time, 86400, &tod);
158 
159         /* time is within a day now */
160         hr = tod / 3600;
161         tod -= hr * 3600;
162 
163         /* time is within an hour now */
164         min = tod / 60;
165         sec = tod - min * 60;
166 
167         temp = (hr << 8) + min;
168 
169         switch (time_alarm) {
170         case MXC_RTC_TIME:
171                 writew(day, ioaddr + RTC_DAYR);
172                 writew(sec, ioaddr + RTC_SECOND);
173                 writew(temp, ioaddr + RTC_HOURMIN);
174                 break;
175         case MXC_RTC_ALARM:
176                 writew(day, ioaddr + RTC_DAYALARM);
177                 writew(sec, ioaddr + RTC_ALRM_SEC);
178                 writew(temp, ioaddr + RTC_ALRM_HM);
179                 break;
180         }
181 }
182 
183 /*
184  * This function updates the RTC alarm registers and then clears all the
185  * interrupt status bits.
186  */
187 static void rtc_update_alarm(struct device *dev, struct rtc_time *alrm)
188 {
189         time64_t time;
190         struct platform_device *pdev = to_platform_device(dev);
191         struct rtc_plat_data *pdata = platform_get_drvdata(pdev);
192         void __iomem *ioaddr = pdata->ioaddr;
193 
194         time = rtc_tm_to_time64(alrm);
195 
196         /* clear all the interrupt status bits */
197         writew(readw(ioaddr + RTC_RTCISR), ioaddr + RTC_RTCISR);
198         set_alarm_or_time(dev, MXC_RTC_ALARM, time);
199 }
200 
201 static void mxc_rtc_irq_enable(struct device *dev, unsigned int bit,
202                                 unsigned int enabled)
203 {
204         struct platform_device *pdev = to_platform_device(dev);
205         struct rtc_plat_data *pdata = platform_get_drvdata(pdev);
206         void __iomem *ioaddr = pdata->ioaddr;
207         u32 reg;
208 
209         spin_lock_irq(&pdata->rtc->irq_lock);
210         reg = readw(ioaddr + RTC_RTCIENR);
211 
212         if (enabled)
213                 reg |= bit;
214         else
215                 reg &= ~bit;
216 
217         writew(reg, ioaddr + RTC_RTCIENR);
218         spin_unlock_irq(&pdata->rtc->irq_lock);
219 }
220 
221 /* This function is the RTC interrupt service routine. */
222 static irqreturn_t mxc_rtc_interrupt(int irq, void *dev_id)
223 {
224         struct platform_device *pdev = dev_id;
225         struct rtc_plat_data *pdata = platform_get_drvdata(pdev);
226         void __iomem *ioaddr = pdata->ioaddr;
227         unsigned long flags;
228         u32 status;
229         u32 events = 0;
230 
231         spin_lock_irqsave(&pdata->rtc->irq_lock, flags);
232         status = readw(ioaddr + RTC_RTCISR) & readw(ioaddr + RTC_RTCIENR);
233         /* clear interrupt sources */
234         writew(status, ioaddr + RTC_RTCISR);
235 
236         /* update irq data & counter */
237         if (status & RTC_ALM_BIT) {
238                 events |= (RTC_AF | RTC_IRQF);
239                 /* RTC alarm should be one-shot */
240                 mxc_rtc_irq_enable(&pdev->dev, RTC_ALM_BIT, 0);
241         }
242 
243         if (status & RTC_1HZ_BIT)
244                 events |= (RTC_UF | RTC_IRQF);
245 
246         if (status & PIT_ALL_ON)
247                 events |= (RTC_PF | RTC_IRQF);
248 
249         rtc_update_irq(pdata->rtc, 1, events);
250         spin_unlock_irqrestore(&pdata->rtc->irq_lock, flags);
251 
252         return IRQ_HANDLED;
253 }
254 
255 /*
256  * Clear all interrupts and release the IRQ
257  */
258 static void mxc_rtc_release(struct device *dev)
259 {
260         struct platform_device *pdev = to_platform_device(dev);
261         struct rtc_plat_data *pdata = platform_get_drvdata(pdev);
262         void __iomem *ioaddr = pdata->ioaddr;
263 
264         spin_lock_irq(&pdata->rtc->irq_lock);
265 
266         /* Disable all rtc interrupts */
267         writew(0, ioaddr + RTC_RTCIENR);
268 
269         /* Clear all interrupt status */
270         writew(0xffffffff, ioaddr + RTC_RTCISR);
271 
272         spin_unlock_irq(&pdata->rtc->irq_lock);
273 }
274 
275 static int mxc_rtc_alarm_irq_enable(struct device *dev, unsigned int enabled)
276 {
277         mxc_rtc_irq_enable(dev, RTC_ALM_BIT, enabled);
278         return 0;
279 }
280 
281 /*
282  * This function reads the current RTC time into tm in Gregorian date.
283  */
284 static int mxc_rtc_read_time(struct device *dev, struct rtc_time *tm)
285 {
286         time64_t val;
287 
288         /* Avoid roll-over from reading the different registers */
289         do {
290                 val = get_alarm_or_time(dev, MXC_RTC_TIME);
291         } while (val != get_alarm_or_time(dev, MXC_RTC_TIME));
292 
293         rtc_time64_to_tm(val, tm);
294 
295         return 0;
296 }
297 
298 /*
299  * This function sets the internal RTC time based on tm in Gregorian date.
300  */
301 static int mxc_rtc_set_mmss(struct device *dev, time64_t time)
302 {
303         struct platform_device *pdev = to_platform_device(dev);
304         struct rtc_plat_data *pdata = platform_get_drvdata(pdev);
305 
306         /*
307          * TTC_DAYR register is 9-bit in MX1 SoC, save time and day of year only
308          */
309         if (is_imx1_rtc(pdata)) {
310                 struct rtc_time tm;
311 
312                 rtc_time64_to_tm(time, &tm);
313                 tm.tm_year = 70;
314                 time = rtc_tm_to_time64(&tm);
315         }
316 
317         /* Avoid roll-over from reading the different registers */
318         do {
319                 set_alarm_or_time(dev, MXC_RTC_TIME, time);
320         } while (time != get_alarm_or_time(dev, MXC_RTC_TIME));
321 
322         return 0;
323 }
324 
325 /*
326  * This function reads the current alarm value into the passed in 'alrm'
327  * argument. It updates the alrm's pending field value based on the whether
328  * an alarm interrupt occurs or not.
329  */
330 static int mxc_rtc_read_alarm(struct device *dev, struct rtc_wkalrm *alrm)
331 {
332         struct platform_device *pdev = to_platform_device(dev);
333         struct rtc_plat_data *pdata = platform_get_drvdata(pdev);
334         void __iomem *ioaddr = pdata->ioaddr;
335 
336         rtc_time64_to_tm(get_alarm_or_time(dev, MXC_RTC_ALARM), &alrm->time);
337         alrm->pending = ((readw(ioaddr + RTC_RTCISR) & RTC_ALM_BIT)) ? 1 : 0;
338 
339         return 0;
340 }
341 
342 /*
343  * This function sets the RTC alarm based on passed in alrm.
344  */
345 static int mxc_rtc_set_alarm(struct device *dev, struct rtc_wkalrm *alrm)
346 {
347         struct platform_device *pdev = to_platform_device(dev);
348         struct rtc_plat_data *pdata = platform_get_drvdata(pdev);
349 
350         rtc_update_alarm(dev, &alrm->time);
351 
352         memcpy(&pdata->g_rtc_alarm, &alrm->time, sizeof(struct rtc_time));
353         mxc_rtc_irq_enable(dev, RTC_ALM_BIT, alrm->enabled);
354 
355         return 0;
356 }
357 
358 /* RTC layer */
359 static struct rtc_class_ops mxc_rtc_ops = {
360         .release                = mxc_rtc_release,
361         .read_time              = mxc_rtc_read_time,
362         .set_mmss64             = mxc_rtc_set_mmss,
363         .read_alarm             = mxc_rtc_read_alarm,
364         .set_alarm              = mxc_rtc_set_alarm,
365         .alarm_irq_enable       = mxc_rtc_alarm_irq_enable,
366 };
367 
368 static int mxc_rtc_probe(struct platform_device *pdev)
369 {
370         struct resource *res;
371         struct rtc_device *rtc;
372         struct rtc_plat_data *pdata = NULL;
373         u32 reg;
374         unsigned long rate;
375         int ret;
376         const struct of_device_id *of_id;
377 
378         pdata = devm_kzalloc(&pdev->dev, sizeof(*pdata), GFP_KERNEL);
379         if (!pdata)
380                 return -ENOMEM;
381 
382         of_id = of_match_device(imx_rtc_dt_ids, &pdev->dev);
383         if (of_id)
384                 pdata->devtype = (enum imx_rtc_type)of_id->data;
385         else
386                 pdata->devtype = pdev->id_entry->driver_data;
387 
388         res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
389         pdata->ioaddr = devm_ioremap_resource(&pdev->dev, res);
390         if (IS_ERR(pdata->ioaddr))
391                 return PTR_ERR(pdata->ioaddr);
392 
393         pdata->clk_ipg = devm_clk_get(&pdev->dev, "ipg");
394         if (IS_ERR(pdata->clk_ipg)) {
395                 dev_err(&pdev->dev, "unable to get ipg clock!\n");
396                 return PTR_ERR(pdata->clk_ipg);
397         }
398 
399         ret = clk_prepare_enable(pdata->clk_ipg);
400         if (ret)
401                 return ret;
402 
403         pdata->clk_ref = devm_clk_get(&pdev->dev, "ref");
404         if (IS_ERR(pdata->clk_ref)) {
405                 dev_err(&pdev->dev, "unable to get ref clock!\n");
406                 ret = PTR_ERR(pdata->clk_ref);
407                 goto exit_put_clk_ipg;
408         }
409 
410         ret = clk_prepare_enable(pdata->clk_ref);
411         if (ret)
412                 goto exit_put_clk_ipg;
413 
414         rate = clk_get_rate(pdata->clk_ref);
415 
416         if (rate == 32768)
417                 reg = RTC_INPUT_CLK_32768HZ;
418         else if (rate == 32000)
419                 reg = RTC_INPUT_CLK_32000HZ;
420         else if (rate == 38400)
421                 reg = RTC_INPUT_CLK_38400HZ;
422         else {
423                 dev_err(&pdev->dev, "rtc clock is not valid (%lu)\n", rate);
424                 ret = -EINVAL;
425                 goto exit_put_clk_ref;
426         }
427 
428         reg |= RTC_ENABLE_BIT;
429         writew(reg, (pdata->ioaddr + RTC_RTCCTL));
430         if (((readw(pdata->ioaddr + RTC_RTCCTL)) & RTC_ENABLE_BIT) == 0) {
431                 dev_err(&pdev->dev, "hardware module can't be enabled!\n");
432                 ret = -EIO;
433                 goto exit_put_clk_ref;
434         }
435 
436         platform_set_drvdata(pdev, pdata);
437 
438         /* Configure and enable the RTC */
439         pdata->irq = platform_get_irq(pdev, 0);
440 
441         if (pdata->irq >= 0 &&
442             devm_request_irq(&pdev->dev, pdata->irq, mxc_rtc_interrupt,
443                              IRQF_SHARED, pdev->name, pdev) < 0) {
444                 dev_warn(&pdev->dev, "interrupt not available.\n");
445                 pdata->irq = -1;
446         }
447 
448         if (pdata->irq >= 0)
449                 device_init_wakeup(&pdev->dev, 1);
450 
451         rtc = devm_rtc_device_register(&pdev->dev, pdev->name, &mxc_rtc_ops,
452                                   THIS_MODULE);
453         if (IS_ERR(rtc)) {
454                 ret = PTR_ERR(rtc);
455                 goto exit_put_clk_ref;
456         }
457 
458         pdata->rtc = rtc;
459 
460         return 0;
461 
462 exit_put_clk_ref:
463         clk_disable_unprepare(pdata->clk_ref);
464 exit_put_clk_ipg:
465         clk_disable_unprepare(pdata->clk_ipg);
466 
467         return ret;
468 }
469 
470 static int mxc_rtc_remove(struct platform_device *pdev)
471 {
472         struct rtc_plat_data *pdata = platform_get_drvdata(pdev);
473 
474         clk_disable_unprepare(pdata->clk_ref);
475         clk_disable_unprepare(pdata->clk_ipg);
476 
477         return 0;
478 }
479 
480 #ifdef CONFIG_PM_SLEEP
481 static int mxc_rtc_suspend(struct device *dev)
482 {
483         struct rtc_plat_data *pdata = dev_get_drvdata(dev);
484 
485         if (device_may_wakeup(dev))
486                 enable_irq_wake(pdata->irq);
487 
488         return 0;
489 }
490 
491 static int mxc_rtc_resume(struct device *dev)
492 {
493         struct rtc_plat_data *pdata = dev_get_drvdata(dev);
494 
495         if (device_may_wakeup(dev))
496                 disable_irq_wake(pdata->irq);
497 
498         return 0;
499 }
500 #endif
501 
502 static SIMPLE_DEV_PM_OPS(mxc_rtc_pm_ops, mxc_rtc_suspend, mxc_rtc_resume);
503 
504 static struct platform_driver mxc_rtc_driver = {
505         .driver = {
506                    .name        = "mxc_rtc",
507                    .of_match_table = of_match_ptr(imx_rtc_dt_ids),
508                    .pm          = &mxc_rtc_pm_ops,
509         },
510         .id_table = imx_rtc_devtype,
511         .probe = mxc_rtc_probe,
512         .remove = mxc_rtc_remove,
513 };
514 
515 module_platform_driver(mxc_rtc_driver)
516 
517 MODULE_AUTHOR("Daniel Mack <daniel@caiaq.de>");
518 MODULE_DESCRIPTION("RTC driver for Freescale MXC");
519 MODULE_LICENSE("GPL");
520 
521 

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